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Eopneumatosuchus colberti Crompton and Smith, 1980, known from a single partial skull, is an enigmatic crocodylomorph from the Lower Jurassic Kayenta Formation. In spite of its unique morphology, an exceptionally pneumatic braincase, and presence during a critical time period of crocodylomorph evolution, relatively little is known about this taxon. Here, we redescribe the external cranial morphology of E. colberti, present novel information on its endocranial anatomy, evaluate its phylogenetic position among early crocodylomorphs, and seek to better characterize its ecology. Our examination clarifies key aspects of cranial suture paths and braincase anatomy. Comparisons with related taxa (e.g., Protosuchus haughtoni) demonstrate that extreme pneumaticity of the braincase may be more widespread in protosuchids than previously appreciated. Computed tomography scans reveal an endocranial morphology that resembles that of other early crocodylomorphs, in particular the noncrocodyliform crocodylomorph Almadasuchus figarii. There are, however, key differences in olfactory bulb and cerebral hemisphere morphology, which demonstrate the endocranium of crocodylomorphs is not as conserved as previously hypothesized. Our phylogenetic analysis recovers E. colberti as a close relative of Protosuchus richardsoni and Edentosuchus tienshanensis, contrasting with previous hypotheses of a sister group relationship with Thalattosuchia. Previous work suggested the inner ear has some similarities to semi-aquatic crocodyliforms, but the phylogenetic placement of E. colberti among protosuchids with a terrestrial postcranial skeletal morphology complicates paleoecological interpretation.

Peer reviewed: True, Among terrestrial vertebrates, only crown birds (Neornithes) rival mammals in terms of relative brain size and behavioural complexity. Relatedly, the anatomy of the avian central nervous system and associated sensory structures, such as the vestibular system of the inner ear, are highly modified with respect to those of other extant reptile lineages. However, a dearth of three-dimensional Mesozoic fossils has limited our knowledge of the origins of the distinctive endocranial structures of crown birds. Traits such as an expanded, flexed brain, a ventral connection between the brain and spinal column, and a modified vestibular system have been regarded as exclusive to Neornithes. Here, we demonstrate all of these ‘advanced’ traits in an undistorted braincase from an Upper Cretaceous enantiornithine bonebed in south-eastern Brazil. Our discovery suggests that these crown bird-like endocranial traits may have originated prior to the split between Enantiornithes and the more crownward portion of avian phylogeny over 140 million years ago, while coexisting with a remarkably plesiomorphic cranial base and posterior palate region. Altogether, our results support the interpretation that the distinctive endocranial morphologies of crown birds and their Mesozoic relatives are affected by complex trade-offs between spatial constraints during development.

The late Paleozoic temnospondyl Sclerocephalus formed an aquatic top predator in various central European lakes of the late Carboniferous and early Permian. Despite hundreds of specimens spanning a wide range of sizes, knowledge of the endocranium (braincase and palatoquadrate) remained very insufficient in Sclerocephalus and other stereospondylomorphs because even large skulls had unossified endocrania. A new specimen from a stratigraphically ancient deposit at St. Wendel in southwestern Germany is recognized as representing a new taxon, S. concordiae new species, and reveals a completely ossified endocranium. The sphenethmoid was completely ossified from the basisphenoid to the anterior ethmoid region, co-ossified with the parasphenoid, and the basipterygoid joint was fully established. The pterygoid bears a slender, S-shaped epipterygoid, which formed a robust pillar lateral to the braincase. The massive stapes was firmly sutured to the parasphenoid. In the temnospondyl endocranium, character evolution involved various changes in the epipterygoid region, which evolved distinct morphologies in each of the major clades.UUID: http://zoobank.org/5e6d2078-eacf-4467-84cf-a12efcae7c0b

Middle meningeal vessels, dural venous sinuses, and emissary veins leave imprints and canals in the endocranium, and thus provide evidence of vascular patterns in osteological samples. This paper investigates whether craniovascular morphology undergoes changes in craniosynostotic human skulls, and if specific alterations may reflect structural and functional relationships in the cranium. The analyzed osteological sample consists of adult individuals with craniosynostoses generally associated with dolichocephalic or brachycephalic proportions, and a control sample of anatomically normal adult skulls. The pattern and dominance of the middle meningeal artery, the morphology of the confluence of the sinuses, and the size and number of the emissary foramina were evaluated. Craniovascular morphology was more diverse in craniosynostotic skulls than in anatomically normal skulls. The craniosynostotic skulls often displayed enlarged occipito-marginal sinuses and more numerous emissary foramina. The craniosynostotic skulls associated with more brachycephalic morphology often presented enlarged emissary foramina, while the craniosynostotic skulls associated with dolichocephalic effects frequently displayed more developed posterior branches of the middle meningeal artery. The course and morphology of the middle meningeal vessels, dural venous sinuses, and emissary veins in craniosynostotic skulls can be related to the redistribution of growth forces, higher intracranial pressure, venous hypertension, or thermal constraints. These functional and structural changes are of interest in both anthropology and medicine, involving epigenetic traits that concern the functional and ontogenetic balance between soft and hard tissues.

A detailed anatomy of the braincase and stapes of the subadult specimen of Diadectes absitus from early Permian sediments of Germany are described for the first time based on the high-resolution X-ray microcomputed tomography. In contrast to previous studies of Diadectes, the bones of the braincase (opisthotic, prootic, supraoccipital, basioccipital, exoccipital, basisphenoid, and sphenethmoid), and parasphenoid of D. absitus are not co-ossified, but suturally defined. This has allowed for a reconstruction of a complete braincase with all sutures between the individual bones. The opisthotic, prootic, and supraocciptal contain a well-preserved endosseous labyrinth. The three-dimensional-reconstruction of its cavities shows a well-preserved vestibule, three semicircular canals, and well-developed cochlear recess. In addition, a shallow subarcuate fossa is present on the ventral surface of the supraoccipital, which lies medial to the anterior semicircular canal. A typical feature of the diadectid braincase is the presence of the otic tube leading from the fenestra vestibuli to the vestibule. A revision of the topology of this structure is presented here. Here, we describe new structures of the stapes, especially in its proximal portion, as well as its position to the fenestra vestibuli. These structures are described for the first time not only in D. absitus, but for the genus.

Bone diseases are commonly found in the fossil record, especially in mammals of the Pleistocene megafauna, which exhibit signs of overload in the articulations. However, pathologies that affect soft tissues are not usually reported, even due to the nature of fossilization that rarely preserves such materials. In paleoneurological research using CT scan and three-dimensional reconstructions of Pleistocene sloths, an anomaly is discovered in the space that houses the pituitary gland, the sella turcica. The tomographic analysis of a Valgipes bucklandi skull revealed a great enlargement at the sella turcica, at the medial region in the body of the basisphenoid bone. The images delimit an enlarged dorsal-ventral projection, measuring approximately 15 mm height, at the tridimensional reconstructed endocranium. Taphonomic processes, such as the action of necrophagous agents, were discarded due to the shape and conditions of the structure, which also showed signs of bone remodeling. Thus, it is possible to affirm that a paleopathological process altered the size of the pituitary gland of the specimen MCT 3993-M, being probably a pituitary tumor.

Environmental properties, and the behavioral habits of species impact sensory cues available for foraging, predator avoidance and inter/intraspecific communication. Consequently, relationships have been discovered between the sensory ecology and brain morphology in many groups of vertebrates. However, these types of studies have remained scare on snake. Here, we investigate the link between endocranial shape and the sensory-related ecology of snakes by comparing 36 species of snakes for which we gathered six sensory-ecology characteristics. We use µCT scanning and 3D geometric morphometrics to compare their endocranium in a phylogenetically informed context. Our results demonstrate that size is a major driver of endocranial shape, with smaller species tending to maximize endocranial volume using a more bulbous shape, while larger species share an elongate endocranial morphology. Phylogeny plays a secondary role with more derived snakes diverging the most in endocranial shape, compared to other species. The activity period influences the shape of the olfactory and optic tract, while the foraging habitat impacts the shape of the cerebellum and cranial nerve regions: structures involved in orientation, equilibrium, and sensory information. However, we found that endocranial morphology alone is not sufficient to predict the activity period of a species without prior knowledge of its phylogenetic relationship. Our results thus demonstrate the value of utilizing endocranial shape as complementary information to size and volume in neurobiological studies.

Dyrosaurids were highly specialized, largely marine, relatives of living crocodylians, and one of the few archosaur lineages to survive the K-Pg extinction. Dyrosaurids lived during the Cretaceous to the Eocene and represent a unique combination of morphology and ecology not seen in living crocodylians. Little is known about their endocranial anatomy, leaving many questions about their neurosensory adaptations unaddressed. Recently, µCT (micro-computed tomography) scans were made of a well-preserved skull of Rhabdognathus, a Paleocene dyrosaurid from Mali. This marks the first time the braincase and neurosensory features of a dyrosaurid have been examined using CT. We focus our attention to three specific internal structures: the cranial endocast; the inner ear; and the paratympanic sinuses. The cranial endocast of Rhabdognathus revealed novel features including a unique conformation of its paratympanic system, a prominent dorsal venous system that communicates with the external skull table, extremely enlarged tympanic vestibules that meet at the midline of the endocranium, a prominent spherical cerebrum, and elongate olfactory tracts accounting for half the total endocast length. The bizarre laterally facing lateral Eustachian foramen of dyrosaurids is now understood to be a complex fossa including both a ventrally directed lateral Eustachian foramen and a laterally directed foramen for the basioccipital diverticulum. A novel median pterygopharyngeal canal was discovered connecting the pharynx to the adductor chamber. These revelations require a reinterpretation of the associated external foramina visible on the posterior of the skull in dyrosaurids and potentially their close relatives the pholidosaurids. The olfactory tract terminates in an enlarged olfactory region possessing complex bony projections—a unique morphology perhaps serving to increase surface area for olfaction. The inner ear of Rhabdognathus exhibits characteristics seen in both Pelagosaurus and Gavialis. The vestibule is spherical, as in Gavialis, but is significantly expanded. The semicircular canals are enlarged but pyramidal in shape as in the thalattosuchian Pelagosaurus. The proportion of the cochlear length to total endosseous labyrinth height is roughly 0.5 in Rhabdognathus implying that the hearing capabilities resemble that of thalattosuchians. A suite of expanded sense organs (e.g., bony olfactory lamina; hypertrophied vestibule of the inner ear), and the clear expansion of the cerebrum to a more symmetrical and spherical shape suggest that dyrosaurids possess neuroanatomical modifications facilitating an agile predatory near-shore ecology.

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq Terrestrial Cetartiodactyla arose in North America and Europe during the early Eocene and diversified, giving rise, among others, to the clade Ruminantia, which includes Cervidae. Cervidae is divided into Cervinae, European and Asian deer, and Capreolinae, the American deer. The formation of the Isthmus of Panama (late Pliocene) enabled the biotic interchange between the continents of North and Central Americas, and South America (Great American Biotic Interchange), where the Cervidae radiated quickly after their arrival. Paleoneurology is a branch of paleontology that is dedicated to the study of neurological evolution through time. Using computed tomography techniques, it is possible to access the endocranial morphology of extinct species. Here, we studied the brain endocast of the extinct late Pleistocene cervid Antifer ensenadensis from southern Brazil, one of the largest forms that lived on this continent. Comparative morphology, geometric morphometrics, and encephalization quotients were employed to compare this extinct species with other American and Eurasian forms. For this purpose, specimens from the Touro Passo Formation (Upper Pleistocene), southern Brazil, were scanned, and virtual models of the endocranial cavity were generated. The analyzed endocasts demonstrate that A. ensenadensis had a gyrencephalic brain, showing a prominent longitudinal sinus (=sagittal superior sinus), which is also observed in the large South American cervid Blastocerus dichotomus. Also, the endocast is anteroposteriorly elongated and rhomboid in shape. The geometric morphometric analysis suggested a clear and linear allometric trend between brain endocast size and shape and highlights A. ensenadensis as an extreme form within the analyzed cervids regarding brain morphology. The encephalization coefficient of A. ensenadensis (0.68, Jerison, 1973; 0.63, Eisenberg, 1981) is within the range of extant cervids (0.64 - 1, Jerison, 1973; 0.60 - 1.06, Eisenberg, 1981) - suggesting that the pattern of encephalization of South American forms was already established at least since the end of the Pleistocene. Os Cetartiodactyla terrestres surgiram na América do Norte e Europa durante o Eoceno inicial e irradiaram-se, dando origem, dentre outros, aos Ruminantia – onde está incluído o grupo Cervidae. O clado Cervidae atualmente divide-se em Cervinae, cervídeos europeus e asiáticos, e Capreolinae, os cervídeos americanos. A formação do Istmo do Panamá (Plioceno final) possibilitou a troca biótica entre os continentes da América do Norte e Central, e a América do Sul, onde os cervídeos capreolíneos Odocoileini irradiaram-se rapidamente após seu ingresso no continente. A paleoneurologia é um ramo da paleontologia que se dedica ao estudo da evolução neurológica através do tempo. Utilizando técnicas de tomografia computadorizada, é possível acessar a morfologia endocraniana de espécies extintas. Na presente dissertação, estudamos moldes endocranianos do encéfalo do cervídeo extinto Antifer ensenadensis (Pleistoceno final), uma das maiores formas que viveram neste continente. Para isso, espécimes provenientes da Formação Touro Passo (Pleistoceno Superior), oeste do Rio Grande do Sul, foram tomografados e modelos virtuais da cavidade endocraniana foram gerados. Como metodologia, foi utilizada morfologia comparada com outros cervídeos, morfometria geométrica e coeficiente de encefalização. Os moldes endocranianos analisados demonstram que A. ensenadensis possuiu um cérebro girencefálico, possuindo o seio sagital superior saliente na superfície do molde endocraniano, além de ser anteroposteriormente alongado e com formato romboide. A análise de morfometria geométrica sugeriu uma tendência alométrica linear entre o tamanho e a forma do molde endocraniano cerebral e destaca A. ensenadensis como uma forma extrema dentro dos cervídeos analisados, em relação à morfologia cerebral. O coeficiente de encefalização de Antifer ensenadensis (0.68, Jerison, 1973; 0.63, Eisenberg, 1981) está dentro da variação dos cervídeos atuais (0.64 – 1, Jerison, 1973; 0.60 – 1.06, Eisenberg, 1981) – sugerindo que o padrão de encefalização das formas sul-americanas já estava estabelecido pelo menos desde o final do Pleistoceno.

Recently, the morphology and encephalization of the brain endocast of the Triassic non-mammaliaform probainognathian cynodont Riograndia guaibensis were studied. Here, we analyzed the brain endocast of an additional specimen of this species. The new endocast shows well-defined olfactory bulbs and a median sulcus dividing the hemispheres, traits that were not clearly observed in the first studied specimen. Encephalization quotients were also calculated, revealing similar values to other non-mammaliaform cynodonts and lower than those of the first analyzed specimen. The analyzed cranium is slightly larger than the first studied one and may represent an advanced ontogenetic stage. Hence, these differences may be related to the intraspecific variation of this cynodont or alternatively, to the preservation of each specimen. Fil: Kerber, Leonardo. Universidade Federal de Santa Maria; Brasil Fil: Ferreira, José Darival. Universidade Federal de Santa Maria; Brasil Fil: Fonseca, Pedro Henrique M.. Universidade Federal do Rio Grande do Sul; Brasil Fil: Franco, Arymatheia. Universidade Federal de Santa Maria; Brasil Fil: Martinelli, Agustín Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Soares, Marina Bento. Universidade Federal do Rio Grande do Sul; Brasil. Universidade Federal do Rio de Janeiro; Brasil Fil: Ribeiro, Ana Maria. Universidade Federal do Rio Grande do Sul; Brasil

10 pages; International audience; Hyaenodonts are extinct placental mammals with a carnivorous diet. Their phylogenetic position among mammals and the relationships within Hyaenodonta are at present partially unresolved. The endocranium is a structure that has rarely been studied in this clade. Using 3D tomography, we studied the endocranium of the European hyaenodont Eurotherium theriodis, discovered in Egerkingen (Switzerland, Lutetian, middle Eocene). Eurotherium theriodis has an endocranium morphology that supports an increase in size of the cerebrum relative to the cerebellum over time within the Hyaenodontoidea. The endocranium also supports a complexification of the cerebrum (i.e., at least two furrows per cerebral hemisphere) within the Hyaenodontoidea and allows us to envisage an increase of the encephalization quotient (EQ), over time. Based on morphology, we consider that its endocranium does not depart from that of the hyaenodontoids known in the Lutetian, Bartonian, and Priabonian of Europe, being less complex than that of the hypercarnivorous Hyaenodon. However, the morphology of its olfactory bulbs and turbinates is similar to that observed in Hyaenodon. The large size of the turbinates of E. theriodis is regarded to be the result of a possible scavenger ecology and agrees with the meat/bone diet envisaged based on the analysis of the morphology of the skull and teeth.

Birds and crocodiles show radically different patterns of brain development, and it is of interest to compare these to determine the pattern of brain growth expected in dinosaurs. Here we provide atlases of 3D brain (endocast) reconstructions for Alligator mississippiensis (alligator) and Struthio camelus (ostrich) through ontogeny, prepared as digital restorations from CT scans of stained head and dry skull specimens. Our morphometric analysis confirms that ostrich brains do not change significantly in shape during postnatal growth, whereas alligator brains unfold from a cramped bird-like shape in the hatchling to an elongate, straight structure in the adult. We confirm that birds exhibit paedomorphic dinosaur endocranial traits such as retaining an enlarged and compact brain shape in the adult, whereas crocodiles show peramorphic traits where the brain elongates with growth as the skull elongates. These atlases of ontogenetic stages of modern bird and crocodilian endocrania provide a basis for comparison of non-avian dinosaur endocasts and consideration of the divergence of the "avian" and "crocodilian" modes of brain development and heterochronic change on phylogenies.

Parahenodus atancensis de Miguel Chaves, Ortega& Pérez-García, 2018 is a recently described bizarre cyamodontoid placodont, based on a partial but well-preserved Spanish Upper Triassic skull. It was identified as the sister taxon of the German highly specialized Henodus chelyops Huene, 1936. The use of micro-computed tomography has been able to significantly increase knowledge of the cranial anatomy of Parahenodus atancensis by the characterization of several bones and structures previously unknown for this taxon, as well as to obtain a partial reconstruction of its brain endocast and associated endocranial structures, poorly known in most Triassic sauropterygians. In addition, we identify several synapomorphies of the braincase of Cyamodontoidea so far unknown in Henodontidae, improving knowledge about this clade. The study of the endocranium and neurosensory structures of Parahenodus atancensis suggests a relatively lower reliance on vision, the pineal system and the pituitary than in other Triassic sauropterygians.

A diverse fossil record of Cervidae (Mammalia) has been documented in the South American Pleistocene, when these animals arrived during the Great American Biotic Interchange. Using computed tomography-scanning techniques, it is possible to access the endocranial morphology of extinct species. Here, we studied the brain endocast of the extinct late Pleistocene cervid Antifer ensenadensis from southern Brazil, one of the largest forms that lived on this continent, using comparative morphology, geometric morphometrics, and encephalization quotients. The analyzed endocasts demonstrate that A. ensenadensis had a gyrencephalic brain, showing a prominent longitudinal sinus (=sagittal superior sinus), which is also observed in the large South American cervid Blastocerus dichotomus. The encephalization quotient is within the variation of extant cervids, suggesting maintenance of the pattern of encephalization from at least the late Pleistocene. Geometric morphometric analysis suggested a clear and linear allometric trend between brain endocast size and shape, and highlights A. ensenadensis as an extreme form within the analyzed cervids regarding brain morphology.

Narwhals (Monodon monoceros) and belugas (Delphinapterus leucas) are the only extant members of the Monodontidae, and are charismatic Arctic‐endemic cetaceans that are at risk from global change. Investigating the anatomy and sensory apparatuses of these animals is essential to understanding their ecology and evolution, and informs efforts for their conservation. Here, we use X‐ray CT scans to compare aspects of the endocranial and inner ear labyrinth anatomy of extant monodontids and use the overall morphology to draw larger inferences about the relationship between morphology and ecology. We show that differences in the shape of the brain, vasculature, and neural canals of both species may relate to differences in diving and other behaviors. The cochleae are similar in morphology in the two species, signifying similar hearing ranges and a close evolutionary relationship. Lastly, we compare two different methods for calculating 90var – a calculation independent of body size that is increasingly being used as a proxy for habitat preference. We show that a ‘direct’ angular measurement method shows significant differences between Arctic and other habitat preferences, but angle measurements based on planes through the semicircular canals do not, emphasizing the need for more detailed study and standardization of this measurement. This work represents the first comparative internal anatomical study of the endocranium and inner ear labyrinths of this small clade of toothed whales.

The aim of this work is to review the spectrum of sinonasal lesions that extend to the endocranium and to present key points that may narrow the differential diagnosis. The most frequent sinonasal lesions that extend into the endocranium are malignant; however, benign entities are not unusual. Imaging diagnosis is difficult because malignant lesions and benign entities share similar clinical, epidemiologic, and imaging features. Tumor features in relation to bone, intratumor homogeneity and structure, magnetic resonance imaging signal, along with clinical and epidemiologic aspects may allow an appropriate diagnostic focus with important management implications.

The purpose of this study was to examine the pattern of postnatal brain growth in two wild canid species: the coyote (Canis latrans) and gray wolf (Canis lupus). Adult regional and total brain volume differences were also compared between the two species as well as within each species by sex. Three-dimensional virtual endocasts of endocranial airspace were created from computed tomography scans of 52 coyote skulls (28 female, 24 male; 1 day to 13.4 years) and 46 gray wolf skulls (25 female, 21 male; 1 day to 7.9 years). Age was known in coyotes or estimated from dentition patterns in wolves. The 95% asymptotic growth of the endocranium is completed by 21 weeks in male and 17.5 weeks in female coyotes and by 27 weeks in male and 18.5 weeks in female wolves. These ages are well before age at first reproduction (coyote – 40.4 weeks; wolf – 91.25 weeks). Skull growth as measured by centroid size lags behind endocranial growth but is also completed before sexual maturity. Intra- and interspecific comparisons of brain volumes in the adult wolves and coyotes revealed that relative anterior cerebrum (AC) volume was greater in males than females in both species. Relative brain size was greater in the coyote than in the wolf as was relative cerebrum volume. However, relative AC volume and relative cerebellum and brainstem volume was greater in the wolf than coyote. One explanation for the increased AC volume in males compared to females may be related to the role of social information processing. However, additional data are needed to determine the correspondence between regional volumes and functional differences either between or within these species. Nonetheless, these findings provide important baseline data for further studies on wild canid brain variations and development.

International audience; The present 3D Dataset contains the 3D model analyzed in the article : Dubied et al. (2021), Endocranium and ecology of Eurotherium theriodis, a European hyaenodont mammal from the Lutetian. Acta Palaeontologica Polonica 2021, https://doi.org/10.4202/app.00771.2020

International audience; BackgroundPositional skull deformities (PSD) are becoming a daily health concern for craniofacial surgeons. Several reports have indicated that cerebrospinal fluid (CSF) space increases on computed tomography (CT) scans of infants suffering from PSD, suggesting a potential causal link. Here, we describe a semi-automatic method to estimate total brain and CSF volumes quantitatively. We tested the potential correlation between total CSF volume and the occurrence of PSD.MethodsA single-center retrospective study was carried out using 79 CT scans of PSD and 60 CT scans of control subjects. The endocranium was segmented automatically using a three-dimensional deformable surface model, and the brain was segmented using a semi-automatic threshold-based method. Total CSF volume was estimated based on the difference between endocranial and brain volumes.ResultsAutomatic segmentation of the endocranium was possible in 75 CT scans. Semi-automatic brain and CSF volume evaluations were performed in 40 CT scans of infants with PSD (18 = occipital plagiocephaly, 11 = fronto-occipital plagiocephaly, and 11 = posterior brachycephaly) and in six control CT scans. Endocranial and total CSF volumes were not significantly different between patients with PSD and controls. The occipital plagiocephaly group had an enlarged brain volume compared with that in patients in the other groups.ConclusionsTotal CSF volume did not change in infants with PSD, and the results do not support a role for volume changes in CSF in the etiology of PSD. Macrocephaly in patients with occipital plagiocephaly may be a specific etiological factor compared with that in other PSDs.Keywords

The composition of the basicranial axis has been reported in the comparative literature in numerous extant and extinct mammals. The primary components are unpaired endochondral bones: the ethmoid, presphenoid, basisphenoid, and basioccipital. Ventral to these are several dermal elements: included are the unpaired vomer, which is widely present, and three bones with more limited distributions, the paired palatines, the paired pterygoids, and the unpaired parasphenoid. Here, we describe novel dermal structures on the dorsal aspect of the basicranial axis in the rock hyrax, Procavia capensis. This taxon has a medial process of the paired frontal bones that meets on the midline and overlies the presphenoid at its juncture with the ethmoid; we term this the presphenoid process of the frontal. Ventral to the presphenoid process is a second smaller process that is off the midline and presents a facet contacting a boss on the presphenoid; we term this the presphenoid facet of the frontal. Occupying the notch between these two structures is the ethmoidal nerve. We sampled the taxonomically diverse collections of the Section of Mammals, Carnegie Museum of Natural History, and the literature. We found additional instances of interfrontal contact dorsal to the ethmoid and presphenoid in the artiodactyl Neotragus and in various platyrrhine and catarrhine primates resembling the presphenoid process of the frontal of P. capensis. However, we did not find a presphenoid facet of the frontal in Neotragus and the primates, which, therefore, thus far is unique to P. capensis. Additionally, we report the presence of a midline suture on the ventral surface of the presphenoid of neonatal P. capensis, which, to our knowledge, is also unique to this mammal.

Neuroanatomical reconstructions of extinct animals have long been recognized as powerful proxies for palaeoecology, yet our understanding of the endocranial anatomy of dromaeosaur theropod dinosaurs is still incomplete. Here, we used X‐ray computed microtomography (µCT) to reconstruct and describe the endocranial anatomy, including the endosseous labyrinth of the inner ear, of the small‐bodied dromaeosaur, Velociraptor mongoliensis. The anatomy of the cranial endocast and ear were compared with non‐avian theropods, modern birds, and other extant archosaurs to establish trends in agility, balance, and hearing thresholds in order to reconstruct the trophic ecology of the taxon. Our results indicate that V. mongoliensis could detect a wide and high range of sound frequencies (2,368–3,965 Hz), was agile, and could likely track prey items with ease. When viewed in conjunction with fossils that suggest scavenging‐like behaviours in V. mongoliensis, a complex trophic ecology that mirrors modern predators becomes apparent. These data suggest that V. mongoliensis was an active predator that would likely scavenge depending on the age and health of the individual or during prolonged climatic events such as droughts., We reconstructed the brain cavity and inner ear of Velociraptor to better understand its lifestyle and hunting abilities. We found brain structures that are present in modern birds, indicating an exceptional sense of balance and agility. The inner ear also closely resembles that of flightless birds, and Velociraptor had a similar hearing ability to ravens. Velociraptor was an agile predator that relied heavily on its sense of hearing to hunt, although it would scavenge if given the opportunity.

19 pages; International audience; We describe the first endocast reconstruction of a hyaenodont mammal based on X‐ray microtomography. The endocast belongs to the type material of the European hyaenodont Proviverra typica. We performed phylogenetic analysis to contextualize the evolution of endocranial size and complexity in Hyaenodonta. We added several European hyaenodonts and modified several codings of the most recent character–taxon matrix established to question the relationships within Hyaenodonta. Including these new species in a phylogenetic analysis reveals a new clade: Hyaenodontoidea. Comparisons with several previously described endocasts show that there was an increase in complexity in the convolutions of the encephalon within Hyaenodontidae history. Moreover, the analysis of the encephalization quotient reveals that the endocranium of the Hyaenodonta is not smaller than those of fossil Carnivora or some extant Carnivora. Therefore, the extinction of Hyaenodonta may not be linked to the relative size of hyaenodont brains.

Pseudopus apodus (Pallas, 1775) is the largest extant legless species of the subfamily Anguinae (Anguimorpha, Anguidae) living mostly in the sub-arid territories ranging from the Balkan area in Europe to Kazakhstan in Asia. The species of other two genera live in North America, South-East Asia and North Africa (Ophisaurus) and Europe and South-West Asia (Anguis). The interrelationships of Anguinae are unresolved; this is in part the consequence of the insufficient knowledge of the cranial, postcranial and integumentary anatomy of the individual anguine species. The aim of this article is to fulfill this gap in our knowledge of the anguine anatomy. Now, in the first part of the project, the individual bones of the exocranium and visceral endocranium of the anguine legless lizard P. apodus are described in detail. In the present study, P. apodus is revealed to have autoapomorphic features of the skull which clearly distinguish it from Anguis and Ophisaurus. In addition, the study of posthatchling ontogeny of exocranium of P. apodus revealed some features, such as a nasal process of premaxilla being slightly widened in about its mid-length, that are also typical for adults of the Ophisaurus and Anguis species as well as extinct species of Pseudopus. This strongly indicates that peramorphic heterochronic process played role in the evolution of the P. apodus skull. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:460-502, 2017. © 2016 Wiley Periodicals, Inc.

This study investigates the influence of age and sex on the volumes of the pituitary fossa and gland in 91 males and 108 females from Croatia who underwent magnetic resonance imaging of the endocranium for complaints not related to the pituitary gland. Isometric 3DT1 MPRAGE and 3DT1 MPR sequences were obtained on 1.5. Tesla and analysed on ISSA software. The volumes were obtained from the sum of all the areas multiplied by the thickness of the section. The mean volume of the pituitary fossa for males was 1111.1.4 mm3, for females 1354.4.2 mm3. Correlation analysis showed a significant negative correlation (P=0.0.09) between age of the patient, and pituitary volume. Age of the patient and free volume demonstrate a significant positive correlation (P=0.0.01) indicating that the amount of unoccupied space in the pituitary fossa significantly increases with age. Determining general morphological values, as well as variations of pituitary depth and the occupation of the fossa with the pituitary gland is of great help in everyday diagnostic and therapeutic approach.

A medical tomodensitometric study (TDM) was performed on a dry skull from the necropolis of Ancón in Peru. The skull, housed at the Muséum national d'histoire naturelle in Paris, displays an anteroposterior, brachycephalic, oblique, asymmetric, and bilobar deformation. TDM permitted 3-D reconstructions of the skull, endocranium, and vault thickness. The external surface displayed deformation and asymmetry in the bone structures and the endocranium demonstrated deformation and asymmetry in the brain lobes and superficial structures. The TDM demonstration of abnormal variations and pronounced asymmetry in the thickness of the vault strongly suggested that the deformation was ante mortem. The 3-D TDM reconstructions also helped to reconstruct the device used to deform the head.

Cranial anatomical features play a prominent part in the definition of extinctHomotaxa and in species identification in fossils. Thus, knowledge of cranial morphology considered within its geochronological framework is essential to the understanding of the evolution, chronology, and dispersal of the genusHomo. The brain is also a valuable object of study for research on human evolution, because of features such as its large size and a high encephalization quotient in someHomospecies, as well as the complexity of human cognition. However, the joint evolution of endo- and ectocranial anatomies is still little studied, and landmarks representing cerebral anatomy rather than inner cranial bone anatomy are still rarely used. This exploratory piece of research examines endo- and ectocranial profiles in samples representing 3Homotaxa:Homo sapiens(fossil and recent specimens),Homo erectus, andHomo neanderthalensis. We used 2D geometric morphometrics to analyze the shape of the endo- and ectocranial vaults, as well as the relationships between selected anatomical features such as the extension of lobes and bones. The shapes of the vaults were computed using both fixed landmarks and sliding semi-landmarks. The fixed landmarks used for the endocranium were chosen in order to represent cerebral anatomy, in that they are defined by the imprints left by brain structures on the inner bone surface of the skull, and not by bony structures such as the inferior side of cranial sutures. Among other results, we have shown or confirmed specific features in the shape of the endocranium inHomo sapiens, as well as a few differences in the patterns of interplay between lobes and bones. These data, and any further results obtained with larger samples, may provide new insights into the development of the endocranial anatomical pattern inHomo sapiensand of its variability.

The masticatory apparatus amongst closely related carnivoran species raises intriguing questions about the interplay between allometry, function, and phylogeny in defining interspecific variations of cranial morphology. Here we describe the gross structure of the jaw adductor muscles of several species of canid, and then examine how the muscles are scaled across the range of body sizes, phylogenies, and trophic groups. We also consider how the muscles are accommodated on the skull, and how this is influenced by differences of endocranial size. Data were collected for a suite of morphological metrics, including body mass, endocranial volume, and muscle masses and we used geometric morphometric shape analysis to reveal associated form changes. We find that all jaw adductor muscles scale isometrically against body mass, regardless of phylogeny or trophic group, but that endocranial volume scales with negative allometry against body mass. These findings suggest that head shape is partly influenced by the need to house isometrically scaling muscles on a neurocranium scaling with negative allometry. Principal component analysis suggests that skull shape changes, such as the relatively wide zygomatic arches and large sagittal crests seen in species with higher body masses, allow the skull to accommodate a relative enlargement of the jaw adductors compared with the endocranium. Anat Rec, 299:951-966, 2016. © 2016 The Authors The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology Published by Wiley Periodicals, Inc.

The examined Ariidae marine catfish from the Neogene of tropical America consisted of isolated skulls, otoliths and bone fragments, some of which were described independently as otolith-based species or skull-based species. We used three-dimensional digital rendering (microCT) of skull and otolith reconstructions to recognize anatomical patterns including skull-otolith morphology, spatial allocations of otoliths in the endocranium for taxonomic identifications. We recognized isolated Proto-Caribbean otoliths of Cathorops sp. from the late early Miocene to early Pliocene formations and isolated otoliths of †Aspistor verumquadriscutis, †Bagre urumacoensis and Notarius sp. from the late Miocene. We explored the endocrania of four fossil Ariidae skulls from the late Oligocene to late early Miocene Proto-Caribbean to determine their internal otolith-cranial morphology, and we identified and described the skulls of †Bagre protocaribbeanus and †Cantarius nolfi and erected the new species of †Bagre castilloensi n. sp. and †Bagre ornatus n. sp. based on the internal otolith-skull association. The first fossil record of Bagre marinus from the early Pliocene Cubagua Formation to the late Pliocene San Gregorio Formation completed the ariid geochronological sequence. We discuss the differential stages of fossil preservation of bioapatite skulls and aragonite otoliths according to the diagenetic processes as well as the paleoenvironmental conditions in the sedimentary basins. Detailed microCT, 3D reconstructions, X-rays, dry prepared skeletons and digital photos of otolith and skull are shown to elucidate the in-skull otoliths species descriptions.

Objective This study highlights the forensic identification significance of a skeletal anomaly, sella turcica bridging (STB), observable in lateral cephalograms. Materials and Methods A biological profile of an unidentified skeleton was developed by forensic anthropologists, but unique identifiers were required in light of inconclusive DNA results. Upon examination of the endocranium, ossification of the interclinoid ligament of the sella turcica was observed. STB has been clinically associated with craniofacial and dental anomalies that can be observed during life. Analysis of a lateral cephalogram allowed for metric and discrete description of this anomaly. Results and Conclusions In the absence of reliable or time-efficient DNA analysis, skeletal anomalies associated with neurological and/or soft tissue involvement during life may aid in eventual positive identification. STBs are well-documented in clinical literature, but their utility in the process of personal identification has not been addressed in forensic contexts. The area of interest is visualized easily on ante-mortem radiographs which are frequently taken during orthodontic treatment. For this reason, forensic practitioners should be aware of the utility of STB for corroborative and positive identification.